diff options
Diffstat (limited to 'sysdeps/arm/armv6t2/memchr.S')
| -rw-r--r-- | sysdeps/arm/armv6t2/memchr.S | 184 |
1 files changed, 0 insertions, 184 deletions
diff --git a/sysdeps/arm/armv6t2/memchr.S b/sysdeps/arm/armv6t2/memchr.S deleted file mode 100644 index fb4dc8efa3..0000000000 --- a/sysdeps/arm/armv6t2/memchr.S +++ /dev/null @@ -1,184 +0,0 @@ -/* Copyright (C) 2011-2017 Free Software Foundation, Inc. - This file is part of the GNU C Library. - Code contributed by Dave Gilbert <david.gilbert@linaro.org> - - The GNU C Library is free software; you can redistribute it and/or - modify it under the terms of the GNU Lesser General Public - License as published by the Free Software Foundation; either - version 2.1 of the License, or (at your option) any later version. - - The GNU C Library is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - Lesser General Public License for more details. - - You should have received a copy of the GNU Lesser General Public - License along with the GNU C Library. If not, see - <http://www.gnu.org/licenses/>. */ - -#include <sysdep.h> - -@ This memchr routine is optimised on a Cortex-A9 and should work on all ARMv7 -@ and ARMv6T2 processors. It has a fast path for short sizes, and has an -@ optimised path for large data sets; the worst case is finding the match early -@ in a large data set. -@ Note: The use of cbz/cbnz means it's Thumb only - -@ 2011-07-15 david.gilbert@linaro.org -@ Copy from Cortex strings release 21 and change license -@ http://bazaar.launchpad.net/~linaro-toolchain-dev/cortex-strings/trunk/view/head:/src/linaro-a9/memchr.S -@ Change function declarations/entry/exit -@ 2011-12-01 david.gilbert@linaro.org -@ Add some fixes from comments received (including use of ldrd instead ldm) -@ 2011-12-07 david.gilbert@linaro.org -@ Removed cbz from align loop - can't be taken - -@ this lets us check a flag in a 00/ff byte easily in either endianness -#ifdef __ARMEB__ -#define CHARTSTMASK(c) 1<<(31-(c*8)) -#else -#define CHARTSTMASK(c) 1<<(c*8) -#endif - .syntax unified - - .text -#ifdef NO_THUMB - .arm -#else - .thumb - .thumb_func -#endif - .global memchr - .type memchr,%function -ENTRY(memchr) - @ r0 = start of memory to scan - @ r1 = character to look for - @ r2 = length - @ returns r0 = pointer to character or NULL if not found - and r1,r1,#0xff @ Don't think we can trust the caller to actually pass a char - - cmp r2,#16 @ If it's short don't bother with anything clever - blt 20f - - tst r0, #7 @ If it's already aligned skip the next bit - beq 10f - - @ Work up to an aligned point -5: - ldrb r3, [r0],#1 - subs r2, r2, #1 - cmp r3, r1 - beq 50f @ If it matches exit found - tst r0, #7 - bne 5b @ If not aligned yet then do next byte - -10: - @ At this point, we are aligned, we know we have at least 8 bytes to work with - push {r4,r5,r6,r7} - cfi_adjust_cfa_offset (16) - cfi_rel_offset (r4, 0) - cfi_rel_offset (r5, 4) - cfi_rel_offset (r6, 8) - cfi_rel_offset (r7, 12) - - cfi_remember_state - - orr r1, r1, r1, lsl #8 @ expand the match word across to all bytes - orr r1, r1, r1, lsl #16 - bic r6, r2, #7 @ Number of double words to work with * 8 - mvns r7, #0 @ all F's - movs r3, #0 - -15: - ldrd r4,r5, [r0],#8 -#ifndef NO_THUMB - subs r6, r6, #8 -#endif - eor r4,r4, r1 @ Get it so that r4,r5 have 00's where the bytes match the target - eor r5,r5, r1 - uadd8 r4, r4, r7 @ Parallel add 0xff - sets the GE bits for anything that wasn't 0 - sel r4, r3, r7 @ bytes are 00 for none-00 bytes, or ff for 00 bytes - NOTE INVERSION - uadd8 r5, r5, r7 @ Parallel add 0xff - sets the GE bits for anything that wasn't 0 - sel r5, r4, r7 @ chained....bytes are 00 for none-00 bytes, or ff for 00 bytes - NOTE INVERSION -#ifndef NO_THUMB - cbnz r5, 60f -#else - cmp r5, #0 - bne 60f - subs r6, r6, #8 -#endif - bne 15b @ (Flags from the subs above) If not run out of bytes then go around again - - pop {r4,r5,r6,r7} - cfi_adjust_cfa_offset (-16) - cfi_restore (r4) - cfi_restore (r5) - cfi_restore (r6) - cfi_restore (r7) - - and r1,r1,#0xff @ Get r1 back to a single character from the expansion above - and r2,r2,#7 @ Leave the count remaining as the number after the double words have been done - -20: -#ifndef NO_THUMB - cbz r2, 40f @ 0 length or hit the end already then not found -#else - cmp r2, #0 - beq 40f -#endif - -21: @ Post aligned section, or just a short call - ldrb r3,[r0],#1 -#ifndef NO_THUMB - subs r2,r2,#1 - eor r3,r3,r1 @ r3 = 0 if match - doesn't break flags from sub - cbz r3, 50f -#else - eors r3, r3, r1 - beq 50f - subs r2, r2, #1 -#endif - bne 21b @ on r2 flags - -40: - movs r0,#0 @ not found - DO_RET(lr) - -50: - subs r0,r0,#1 @ found - DO_RET(lr) - -60: @ We're here because the fast path found a hit - now we have to track down exactly which word it was - @ r0 points to the start of the double word after the one that was tested - @ r4 has the 00/ff pattern for the first word, r5 has the chained value - cfi_restore_state - cmp r4, #0 - itte eq - moveq r4, r5 @ the end is in the 2nd word - subeq r0,r0,#3 @ Points to 2nd byte of 2nd word - subne r0,r0,#7 @ or 2nd byte of 1st word - - @ r0 currently points to the 2nd byte of the word containing the hit - tst r4, # CHARTSTMASK(0) @ 1st character - bne 61f - adds r0,r0,#1 - tst r4, # CHARTSTMASK(1) @ 2nd character - ittt eq - addeq r0,r0,#1 - tsteq r4, # (3<<15) @ 2nd & 3rd character - @ If not the 3rd must be the last one - addeq r0,r0,#1 - -61: - pop {r4,r5,r6,r7} - cfi_adjust_cfa_offset (-16) - cfi_restore (r4) - cfi_restore (r5) - cfi_restore (r6) - cfi_restore (r7) - - subs r0,r0,#1 - DO_RET(lr) - -END(memchr) -libc_hidden_builtin_def (memchr) |